A force detection apparatus utilizing a piezoresistance effect has been developed, and an example is disclosed in Patent Literature 1. This type of force detection apparatus includes a substrate and a force transmission block. A mesa gauge configuring a bridge circuit is provided on a main surface of the substrate. For example, the mesa gauge configuring the bridge circuit is disposed in correspondence with sides of a rectangle. The mesa gauge includes a high-sensitive mesa gauge extending in a direction to produce a relatively large change of an electric resistance in accordance to compressive stress, and a low-sensitive mesa gauge extending in a direction producing a relatively small change of an electric resistance in accordance to compressive stress. A mesa lead is further provided on the main surface of the substrate. The mesa lead extends from a connection portion connecting the high-sensitive mesa gauge and the low-sensitive mesa gauge.
The force transmission block is provided so as to cover the high-sensitive mesa gauge, the low-sensitive mesa gauge and the mesa lead, provided on the main surface of the substrate, and to contact a top surface of the high-sensitive mesa gauge, a top surface of the low-sensitive mesa gauge, and a top surface of the mesa lead. When the force transmission block presses the high-sensitive mesa gauge, compressive stress applied to the high-sensitive mesa gauge increases. In this case, electric resistance of the high-sensitive mesa gauge changes by a piezoresistance effect. Force applied to the force transmission block is detected based on the change of the electric resistance.
A force detection apparatus utilizing a piezoresistance effect has been developed. This type of force detection apparatus includes a substrate and a force transmission block. A mesa gauge configuring a bridge circuit is provided on a main surface of the substrate. The force transmission block contacts a top surface of the mesa gauge. When the force transmission block presses the mesa gauge, compressive stress applied to the mesa gauge increases. In this case, electric resistance of the mesa gauge changes by a piezoresistance effect. Force applied to the force transmission block is detected based on the change of the electric resistance.
Each of Patent Literature 2 and Patent Literature 3 discloses a sealed force detection apparatus. The sealed force detection apparatus is characterized by a configuration of a force transmission block connected to a main surface of a substrate around the entire circumference of a mesa gauge.